The best performance upgrade? - JKowners.com : Jeep Wrangler JK Forum
 
LinkBack Thread Tools Display Modes
post #1 of 13 Old 04-06-2011, 07:42 PM Thread Starter
Coonasian
 
Charlie's Avatar
 
Join Date: Jan 2011
Location: Covington, LA USA
Age: 72
Posts: 1,835
Garage
Feedback: 1 reviews
The best performance upgrade?

I took my hardtop and doors off our Rubi Unlimited and it really has a lot more pep without all that weight. I don't know how much that stuff weighs but I know those door are probably 50+ pounds each and the hardtop must be 80-100 pounds. I have never heard this mentioned on the forum. Is it just my imagination?
Charlie is offline  
Sponsored Links
Advertisement
 
post #2 of 13 Old 04-06-2011, 08:24 PM
JKowners Vendor
 
Join Date: Mar 2010
Location: Laguna Hills, CA
Posts: 2,961
Feedback: 7 reviews

Lightening the load helps, regearing makes a huge difference.

Best performance bang for the buck - supercharger.
REBEL OFFROAD is offline  
post #3 of 13 Old 04-07-2011, 08:51 AM
Rock God
 
Join Date: Jun 2010
Posts: 525
Feedback: 0 reviews

I've noticed the same thing Charlie, namely, when that much weight is removed the performance goes up significantly. Yet we see Jeeps all the time that have 140 lb front bumpers, 120 lb winches, 180 lb rear bumper / tire carriers, and 37" to 40" spare tires that are mounted way up high and as far from the vehicles center of mass as possible. Talk about gauranteed screwed up handling and decreased performance, a 40" spare tire is certain to do it. Then add on the weight of rocker gaurds, steel flat fenders, skid plates, and all of your tools and gear in the back of the Jeep. Its a wonder the typical built up Jeep even moves at all. I found it was kind of hard to notice a difference when you added weight, but when you removed that extra weight again, that is when you noticed a night and day improvement in performance. In general, it must be easier to notice an improvement in performance, than it is to notice a decrease in performance.

As for "best performance upgrade", my money is on re-gearing the differentials. An auto trans JK with 35" tires and 3.73 gears, or with 37" tires and 4.10 gears, is going to be turning 1900 RPM at 75 mph on the highway. At 1900 RPM these engines only make 60 horsepower. By changing to 5.13 gears for the 35" tires, or 5.38 gears for the 37" tires, you increase engine RPM to 2600 at 75 mph. At 2600 RPM these engines make 90 horsepower. That is a 50% increase in power, for about $1000 spent on new gears.

2017 Jeep Wrangler Rubicon Recon; 35s - no lift, Warn 9.5 XP-S, ARB Twin Air, SPOD
2017 Jeep Grand Cherokee Trailhawk (wife's Jeep)
2016 Ram Laramie 3500 Megacab 4x4; 6.7 CTD, Aisen, AEV Prospector conversion; 37s, 4.10s, Warn 16.5K
MOPWR2U is offline  
Sponsored Links
Advertisement
 
post #4 of 13 Old 04-07-2011, 09:34 AM
JKO Addict!
 
Bubblegoose1's Avatar
 
Join Date: Feb 2008
Location: WA
Age: 50
Posts: 3,012
Garage
Feedback: 7 reviews

Lighten it up, gearing, tuner and SC seem to be best bang mods.
Bubblegoose1 is offline  
post #5 of 13 Old 04-07-2011, 09:39 AM
JKO Addict!
 
Bubblegoose1's Avatar
 
Join Date: Feb 2008
Location: WA
Age: 50
Posts: 3,012
Garage
Feedback: 7 reviews

Quote:
Originally Posted by MOPWR2U View Post
As for "best performance upgrade", my money is on re-gearing the differentials. An auto trans JK with 35" tires and 3.73 gears, or with 37" tires and 4.10 gears, is going to be turning 1900 RPM at 75 mph on the highway. At 1900 RPM these engines only make 60 horsepower. By changing to 5.13 gears for the 35" tires, or 5.38 gears for the 37" tires, you increase engine RPM to 2600 at 75 mph. At 2600 RPM these engines make 90 horsepower. That is a 50% increase in power, for about $1000 spent on new gears.
A little confused on your rpm numbers. I sit at 2200 rpm at 70 in OD, with 40s. Are your figures without OD?
Bubblegoose1 is offline  
post #6 of 13 Old 04-07-2011, 09:42 AM
Rock God
 
planman's Avatar
 
Join Date: Jan 2009
Location: Billings, MT
Age: 53
Posts: 1,818
Feedback: 0 reviews

Another vote for regearing, tuner, and less weight.

Some combination intakes and exhaust cost the same as regearing, but with inferior results.

Sent from my DROIDX using Tapatalk


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
planman is offline  
post #7 of 13 Old 04-07-2011, 09:55 AM
Rock God
 
2010jk's Avatar
 
Join Date: Apr 2010
Location: Omaha/Nebraska
Posts: 1,540
Feedback: 2 reviews

I'm keeping the weight down on my jk, I run with no spare, chopped front bumper. I think its for every 100 lbs you put on the jk it takes 7-10 hp away, just what I have read. Thats a lot after you think about it, big steel front bumper, winch, rear steel with spare, it all adds up.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


2010 2 door sport, 6 speed,Dark Charcoal Pearl
2010jk is offline  
post #8 of 13 Old 04-07-2011, 01:56 PM
Rock God
 
Join Date: Jun 2010
Posts: 525
Feedback: 0 reviews

Quote:
Originally Posted by Bubblegoose1 View Post
A little confused on your rpm numbers. I sit at 2200 rpm at 70 in OD, with 40s. Are your figures without OD?
Your signature doesn't say so, but I'm assuming you have 5.38 gears. Just add another 5 mph and drop your tire size down to 37" and you'll be turning 2600 RPM in OD, instead of the 2200 RPM you are now at 70 mph.

2017 Jeep Wrangler Rubicon Recon; 35s - no lift, Warn 9.5 XP-S, ARB Twin Air, SPOD
2017 Jeep Grand Cherokee Trailhawk (wife's Jeep)
2016 Ram Laramie 3500 Megacab 4x4; 6.7 CTD, Aisen, AEV Prospector conversion; 37s, 4.10s, Warn 16.5K
MOPWR2U is offline  
post #9 of 13 Old 04-07-2011, 01:58 PM
JKO Addict!
 
nc_fjizzle's Avatar
 
Join Date: Sep 2010
Location: Raleigh, NC
Age: 29
Posts: 3,972
Garage
Feedback: 6 reviews

Damn, another reason to drop a few pounds

Will: 2010 2-Door Rubicon: Check my garage for details

ΣX

Order from River City Offroad
nc_fjizzle is offline  
post #10 of 13 Old 04-07-2011, 02:07 PM
JKO Addict!
 
Bubblegoose1's Avatar
 
Join Date: Feb 2008
Location: WA
Age: 50
Posts: 3,012
Garage
Feedback: 7 reviews

Quote:
Originally Posted by MOPWR2U View Post
Your signature doesn't say so, but I'm assuming you have 5.38 gears. Just add another 5 mph and drop your tire size down to 37" and you'll be turning 2600 RPM in OD, instead of the 2200 RPM you are now at 70 mph.
Oops, forgot that part. Running 5.13s. Odometer checked, gps synced, SC adjusted and Aeroforce synced.


Sent by Braille, with no bumps.
Bubblegoose1 is offline  
post #11 of 13 Old 04-07-2011, 02:12 PM
Wheeler
 
Join Date: Jan 2011
Age: 49
Posts: 70
Feedback: 0 reviews

The late, great Colin Chapman said it best:

Simplify and add lightness

Seriously, when is that not a good idea?
zelatore is offline  
post #12 of 13 Old 04-07-2011, 05:05 PM
Granite Guru
 
Spank's Avatar
 
Join Date: Dec 2010
Location: Colorado Springs, CO
Age: 42
Posts: 100
Feedback: 0 reviews

When I was shopping around for some new bumpers and a winch, I was running my Jeep without a rear bumper and spare. That plus no rear seat (since I never use it) made my Jeep bounce around on the highway like a paranoid sociopath coming off her medication. I actually had to add a little weight to help smooth things out.

'07 Wrangler "Rescue" | 4" Teraflex | 35x12.5x17 KM2's | Eagle Alloy 185's | Rubicon Sliders | 4.10's | JE-Reel DS | OR-FAB/RR Bumpers | Billet Shifters
Spank is offline  
post #13 of 13 Old 04-07-2011, 05:38 PM
Granite Guru
 
JOHN412's Avatar
 
Join Date: Nov 2010
Location: Bangor, PA --Home Blairstown, NJ store
Age: 39
Posts: 402
Feedback: 0 reviews

This was one of the reasons I went with the RRC rear Rock bumper. I didn't want to lose any clearance with a hitch that I'll hardly ever use and wanted max clearance and light weight. I keep two totes full of gear and a stocked tool box in the back of my 2dr. No rear seat of course. I think when I add a winch I'll just take the ends off my front xhd bumper to kinda offset the added weight. And by the way that RRC rear bumper is way heavier than it looks. I was impressed, what don't impress me is the shit finish RR uses on there bumpers. The ups package said 98 pounds with the bumper and hi-lift mounts for the roll cage.

Pics in my profile if anyone cares. The iPhone makes posting them very difficult for me
JOHN412 is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the JKowners.com : Jeep Wrangler JK Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome